A commercial MOSFET-based biosensor with a gold extended-gate electrode

Abstract

This paper presents a commercial metal-oxide-semiconductor field-effect transistor (MOSFET)-based biosensor with a gold extended-gate electrode for the electronic detection of C-reactive protein (CRP). From a component point of view, the commercial MOSFET-based biosensor consists of a commercial MOSFET with a socket for connecting the gold electrode which was fixed on a printed circuit board (PCB) and a reaction-vessel module which was assembled with the gold electrode and the Ag/AgCl reference electrode. The gold electrode with only one gold layer was fabricated on a glass substrate simply and it was used as the extended-gate metal to form a self-assembled monolayer (SAM). The binding of the CRP to anti-CRP was detected by measuring the electrical characteristics of the biosensor. Variation of the drain current before and after the interaction of CRP and anti-CRP was about 1.2mA on the measured IDS-VDS and real-time characteristics. The concentration of the CRP solution was adjusted to 10 μg/ml by dissolving in PBS. The change of surface voltage of the gold extended-gate electrode was about 30mV by IDS-VGS characteristic curve of the commercial MOSFET. Therefore, it is confirmed that the detection of CRP is possible by measuring the drain current of the commercial MOSFET. The proposed biosensor might open up a new possibility for FET-based biosensors with lowcost and simple construction. It is expected that the commercial MOSFET-based biosensor with the gold extended-gate electrode could also be used for detecting various biomarkers by modifying the surface of the gold extended-gate electrode. © 2009 SPIE.